Image 1-Zhaozhi Zheng conducted LC-MSMS analysis of trace organic chemicals

In profile: Zhaozhi Zheng, PhD Candidate

Many urban areas experience both floods and water shortages, sometimes occurring at different times of the year, and sometimes simultaneously as drinking water sources become inundated with stormwater—the water that drains off land, rooves and other surfaces, collecting various pollutants on its way.

The process of stormwater harvesting involves the collection, treatment and storage of stormwater for reuse. While stormwater is often reused for purposes such as flushing, fire-fighting, gardening and irrigation, it needs to be treated to a higher quality to be fit for human consumption.

Zhaozhi Zheng is undertaking research to help develop an efficient and low maintenance stormwater treatment process to purify treated stormwater for potable use.

Large volumes of stormwater are an untapped resource which could relieve water stress to a large extent with appropriate reuse

Zhaozhi Zheng, PhD Candidate

 Zhaozhi, a PhD Candidate in the UNSW School of Civil and Environmental Engineering, completed his Master degree at the National University of Singapore where he learnt about the process of treating domestic wastewater to use as drinking water.

“Compared to recycled domestic wastewater, stormwater is much more easily accepted by the general public as a source of drinking water,” said Zhaozhi.

“Large volumes of stormwater are an untapped resource which could relieve water stress to a large extent with appropriate reuse.”

Current technologies cannot fully remove micropollutants from stormwater, meaning it cannot be classed as higher standard water that can be utilised for drinking. Zhaozhi is addressing this by developing a photo-electrochemical oxidisation method to enable further treatment of biofiltered stormwater.

Zhaozhi Zheng, PhD Candidate

“My research involves a photo-electrochemical oxidation process, with solar energy and low electrical energy, to deal with micropollutants in treated stormwater,” says Zhaozhi.

After my PhD study, this process has great potential to be developed as a mature technology and applied into practice with the help of a Water Sensitive Urban Design system (WUSD)-which is already implemented in Australia for stormwater management.

Zhaozhi believes that makes more sense to develop a passive system that is low cost and low maintenance rather than expend energy exploring potential new water resources and reusing other types of water, as since stormwater is already much cleaner than wastewater and industrial water.

Zhaozhi chose UNSW due to its renowned Water Research Centre and the many experts he could learn from.

“At UNSW, you can always get advice from people all around you and they are all kind enough to share their ideas with you to help you grow,” says Zhaozhi.

“It is a great place with the integration of education and research, and my supervisors Professor Ana Deletic, Dr Kefeng Zhang, Professor Rose Amal and Dr Cui Ying Toe have helped me to develop both my technical and professional skills and, most importantly, contributed to my personal growth.”

Zhaozhi says that if his PhD study goes well, he plans to seek research positions within his current group to further develop his process so that it may be applied to a real stormwater treatment system.

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